The invention described herein relates to the rapid chilling, heating, and dispensing of fluids on-demand.
There are numerous known methods to quickly heat fluids, however there are few options to make a fluid cold quickly. Prior attempts at fluid chilling have used phase change materials such as ice, refrigeration based on compressor and evaporator units, or thermoelectric devices cooled with heat sinks and forced air as the cooling mechanism to transfer heat out of a fluid of interest.
Methods used to directly cool beverage containers, including thermoelectric device methods, suffer from heat conduction barriers caused by the fluid container, the low thermal conductivity of the fluid itself, and the interface to the fluid container. The aforementioned cooling methods are slower than desirable for on-demand chilled beverage dispensing due to these thermal transfer barriers and the large amount of heat that must be extracted from the fluid.
Cooling beverages directly in a container prevents loss of carbonation during chilling, but also takes many minutes to hours to cool a beverage from room temperature to serving temperatures. Fluid thermal conductivity issues within a beverage container can be mitigated by vortexing the liquid, but rapid chilling still requires a bath of ice or near freezing liquid to interface with the beverage container. Existing systems use an ice bath or small compressor-based refrigerator to provide the bath. Ice baths require a significant time to generate, and thus are not ideal for on demand fluid chilling.
Methods using metal tubes, coils, or interior flow plates as the fluid interface are not ideal due to the long flow path required to chill a beverage from room temperature to a desired temperature. The long flow path necessitates that a large volume be occupied in any chilling unit and a large amount of materials be used. Additionally, the geometry of such solutions does not lend themselves well to thermoelectric device-based cooling, as the increased volume results in extra material to chill in addition to increased convective losses. Due to these constraints, the heat transfer rate is reduced unless a phase change material such as ice is put in contact with the fluid interface structure. Additionally, non-pressurized pour-through chillers cause carbonation loss in fluids such as beer during chilling.
A direct thermoelectric device based machine for chilling spirituous beverages, in US 20140250919, extracts heat from a fluid through a finned heat sink the fluid is partially contacting. The thermal transfer rate of this machine is limited by the heat dissipation rate into the environment and the thermal geometry imposed on the fluid by the thermal fins. Heat transfer rate limitations to the environment result in inadequate cooling times for on demand standard size beverages such as beer and water. This device does not teach the optimal geometry to contact a fluid for chilling and heating, or decoupling the heat transfer rates of the thermoelectric device and the environment through the use of a heat reservoir. In addition, the machine is not built to handle carbonated beverage cooling.
The Keurig Kold device in US 20160109175 A1 likewise teaches the use of a thermoelectric device coupled to a cooling tank and a heat pipe at an evaporator section, where the condenser portion of the heat pipe is connected to a heat sink and forced air. In addition, the thermoelectric may be used to form an ice to interface an inner container. This device does not teach the optimal geometry to contact a fluid for chilling and heating, or decoupling the heat transfer rates of the thermoelectric device and the environment through the use of a heat reservoir. The thermoelectric device heat transfer rate is thus decreased due to increased hot side temperature on the thermoelectric device and limited heat transfer rate to the environment. In addition, heat transfer through the fluid is many times slower than the optimal geometry. Reduced cooling rates may result in significant startup times of hours to chill the fluid within the inner reservoir. As a result, a limited number of beverages can be served sequentially, impacting usability and average beverage serving speed.
Publication DE202008004284 U1 discloses a flow through water chiller that transfers heat from water flowing throw a finned heat sink within a chamber, with a thermoelectric device pumping heat out of the fluid to a heat pipe system interfacing to heat sinks or cooling towers cooled with forced air. This device does not teach the optimal geometry to contact a fluid for chilling and heating, or decoupling the heat transfer rates of the thermoelectric device and the environment through the use of a heat reservoir. The thermoelectric device heat transfer rate is thus decreased due to increased hot side temperature on the thermoelectric device and limited heat transfer rate to the environment. Heat transfer through the fluid is many times slower than the optimal geometry. In addition, the machine is not built to handle carbonated beverage cooling.
Publication DE4036210 A1 discloses a fluid chiller where an enclosed zigzag flow pattern within a heat exchange body is connected to thermoelectric elements. The thermoelectric elements are also connected to a heat sink. This device teaches a non-optimal geometry to contact a large volume of fluid for chilling. It also does not teach decoupling the heat transfer rates of the thermoelectric device and the environment through the use of a heat reservoir. The thermoelectric device heat transfer rate is thus decreased due to increased hot side temperature on the thermoelectric device and limited heat transfer rate to the environment. In addition, the volume of fluid that can be cooled rapidly is small.
The Quickchill thermoelectric water chiller from Santa Clara University describes a cooling system with a water chamber, thermoelectric modules, and heat sinks that are attached inside chamber. The device described quotes a 20-minute chilling time. This device does not teach the optimal geometry to contact a fluid for chilling or decoupling the heat transfer rates of the thermoelectric device and the environment through the use of a heat reservoir. The thermoelectric device heat transfer rate is thus decreased due to increased hot side temperature on the thermoelectric device and limited heat transfer rate to the environment. In addition, heat transfer through the fluid is many times slower than the optimal geometry.
Utility model G 9300986.0 proposes a bottle holder for a dosing device for spirituous beverages that is connected to Peltier elements to thermoelectrically cool the bottles fastened to the bottle holder. The cooling of the bottle contents is effected by thermal contact of the bottle with a cooled surface of the bottle holder. As bottles are generally poor heat conductors and, moreover, the bottle holder contacts only a fraction of the bottle surface, the cooling effect of this device is limited.
Laid-Open Print DE 4036210 A1 also describes a continuous flow cooling realized by means of Peltier elements, wherein, in contrast to DE 202008004284 U1, the beverage liquid does not pass through plural parallel flow channels, but through a single zigzag flow channel. In this device, the serving temperature is adjusted by controlling the through flow velocity. In order to avoid icing, cooling down to the freezing point or below is prevented by a control using a temperature sensor. This device does not teach the optimal geometry to contact a fluid for chilling or decoupling the heat transfer rates of the thermoelectric device and the environment through the use of a heat reservoir. The thermoelectric device heat transfer rate is thus decreased due to increased hot side temperature on the thermoelectric device and limited heat transfer rate to the environment. Heat transfer through the fluid is many times slower than the optimal geometry. In addition, the machine is not built to handle carbonated beverage cooling.
Laid-Open Print DE 102007028329 A1 also proposes a continuous flow beverage cooler, wherein the heat exchanger has only a single flow channel for the beverage liquid to pass through. In order to obtain a large heat exchange area with relative small dimensions, the flow channel is configured helically. The cooling of the heat exchanger may be effected, among others, by use of Peltier elements. The geometry of this device does not lend itself well to thermoelectric device based cooling as the increased volume results in extra material to chill in addition to increased convective losses. Due to these constraints, the heat transfer rate is reduced unless a phase change material such as ice is put in contact with the fluid interface structure.
Publication U.S. Pat. No. 6,119,464 describes a tank containing water that serves as a coolant and a coiled beverage duct through which beverage flows. An electronic cooling element serving as a cooling device is fitted to one of the walls of the tank. The electronic cooling element cools the water in the tank by absorbing heat by means of the Peltier effect. The absorbed heat is released by a heat-release fin and a fan. Beer or other beverage fed under pressure into the coiled beverage duct in the tank through an inlet is cooled by the water and poured into a mug or other container through an outlet by opening a cock. The geometry of this device does not lend itself well to thermoelectric device based cooling as the increased volume results in extra material to chill in addition to increased convective losses. Due to these constraints, the heat transfer rate is reduced, increasing chilling time and power consumption.